Income Taxes Unrecognized Tax Benefits (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 144
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	607
Unrecognized Tax Benefits Rollforward (Table Amounts) [Abstract]
Unrecognized tax benefits at beginning of the year	1,223	$ 748	$ 283
Additions based on tax positions related to the current year	187	158	293
Additions for tax positions of prior years	270	400	207
Reductions for tax positions of prior years	(190)	(65)	(23)
Settlements with taxing authorities	(7)	(15)	(7)
Other, net	(2)	(3)	(5)
Net change in unrecognized tax benefits	258	475	465
Unrecognized tax benefits at end of the year	$ 1,481	$ 1,223	$ 748